Fill me in. As I understand the MM it is driven by a PC that controls a BOB. In turn the BOB controls the stepper driver/stepper motors. The PC is running Mach3 and it is told what area it can operate in. It also has proximity detectors that act as a secondary safety. When tripped they tell the BOB "stop the motors". There are also hard stops attached to the axis. I see that this is a piece of steel. I am thinking this needs to be a rubber or a spring to prevent damage.

I see at the top of the web site that there are a series of 5 pictures. Can these be looked at?

The pictures are from the threads.
The hard stops are hard for a reason...they also double as your "hard" registration for squaring the gantry. Not everyone uses it that way - but designed as a hard daily reference.

You only hit them if something goes really wrong in operation.....nothing breaks, but they do the job.

Your signal flow of control is correct. PC uses Mach3 to talk to BOB via LPT or USB port that decodes the control code to dir/step voltage that the gecko (drives) can understand to turn the motors.

Spent the day waiting for Grizzly to call me about returning the bandsaw I bought. When I bought it it stated that it was INDUSTRIAL. So I figured that it could handle bought metal and wood. I was wrong on that. It is industrial wood only. They are being very nice and taking it back as long as I buy another bandsaw. That is fair enough as long as I pay for shipping.

Spend the afternoon milling slots in the y axis rails. That is now done time to start the x axis. The weather right now is windy and chilly. I am going back out and starting to mill the x axis.

FR8Z bearings showed up today. The rest of the parts will be here soon. I bought the steel I needed to make the reduction drive plates. Need to cut the 4 foot plates down to size. Need to create a template and use the plasma to shape them. back to work.

No you are not missing anything, but I do want to have wiggle room if I decide to make some changes down the road. I have been cruising the other sites and see changes that the are making and I decided that since I am waiting on parts right now I would take the time and do it. Anyway I completed the x-axis about ten minutes ago. Tomorrow I will mount them to the frame. Would mount the gear track but waiting on tape from ebay vendor.

got the 3M VHB tape in the mail today. I would like to put the gear rails on tomorrow but it looks like rain. Guess I will work on z axis and put v groove bearings on the spider and mount the 80mm spindle mount. I will need to whittle it down to size on the mill.

I was watching machining videos and noticed that they use formica to create surfaces that need to slide freely. I am going to pick up a couple of samples at Home Depot and use then to make washers for mounting the drive mechanisms. and yes I think I will get some blue ones.

I ordered the gears and belts. Thanks Pete.
I got the 10 inch rotary table I ordered for my mill. I can now mount the steel I ordered and mill out new pack plates. Boy is this thing heavy, 110 lbs wasn't heavy until I hit 60. I can layout the part and just dial in and mill, reset and mill. Tell you how it turns out.

The 72 tooth gears showed up today. They sent 3/8 diameter hole/boar. I will mount them in a collet and drill and boar to 1/2 inch. I noticed the specs on the chart states 3/8 plus or minus 1/16 inch. Pretty sloppy until I thought that 3/8 plus 1/16 = 12mm and if you subtract the 1/16 you get 7.9mm shaft.
So it looks like we think we are getting SAE and are sending Metric. Oh well I am happy they came and will resize them tomorrow. One tiny little step for me and mankind has marched on with the band.

If you are looking for nuts, bolts, bearings etc. try seeing if you have a Fastenal near you. By brother was hunting for odd ball nuts and bolts for his truck and he found them at Fastenal. The prices are about the same as Lowes and Home Depot. I picked up stainless steel 10-24 cap head screws for the same price as zinc plated. They also sell the rectangular tube used for the y-axis.

The rest of my gears and belts showed up today. I drilled out the pulleys to .500 and made the 3 inch axles for the four units. After I dry fitted the unit I scribed the metal plates as described by Mike. Grinder time. The tab came off and I am ready to give welding a try. Hopefully the turkey is the only thing that gets burned tomorrow.

Here is a photo of the reduction drive. Are the gears suppose to be this close?

You can see that the two pulleys are almost touching. The pulleys are 72 and 18 tooth. I ordered the belts from sdp/si, the part number for the original belt was A6b3-080037( 080 is 80 tooth or 16 inches). I ordered two more belts A6b3-088037( 088 is 88 tooth or 17.5 inches). A6b3-090037( 090 is 90 tooth or 18 inches). Will let you know which one works.

Hurshy,
The bad part is that Fastenal used to be about 1/3 less than Home Depot and Lowes when they sold in bulk. Now the are nothing more than a fastener superstore but you can still negotiate price with them. I have used them since 1997.

The 80 tooth belt would only have left you 0.010" clearance according to the Center Designer at SDP-SI where as the 88 should be 0.93" further apart in a perfect world. That is if you are using XL series. Belts are not that perfect but they do stretch a little. When I did my design I ordered for the middle of adjustment and always found it to be a little tighter than the perfect measurement.

Finally crated the bandsaw and it is ready to go back to Grizzly. I am tired that thing weight 600lbs before crating. I finished turning the gears I need for the reduction drive. Need to figure what size set screws would best do the job. I have the steel ready to cut for the covers on the drives. Once the new belts show up I should have them done.

I worked on the Y-axis today. I drilled all the holes needed to mound the v-groove rails. I then took a 7 inch flap grinder to the rails. I removed all the scale and rust. I made sure that all the corners were rounded. I then wiped it down with mineral spirits. I finished by spraying then gloss black. Tomorrow I will drill and mount the gear track and do the same process to the x-axis.

The y rails dried over night and looks good. I screwed the v groove in place with stainless steel screws and lock nuts. I took the camera out to the garage and never took one shot. I did finish drilling all the v groove holes on one of the x rails. I finished by taking the flapper wheel to it and giving it a good coat of gloss black paint. It will be ready tomorrow morning to mount the v groove. Hopefully I will be able to finish the last x rail tomorrow. I have started cutting plywood to support the y-axis assembly before it is welded. I want to get it as square as possible. I don't look forward to welding this unit, but I am going to give it a try.

finished putting the v grooves on the y axis so they are done and ready to mount on the carriage. finished mounting the v groove on the x axis. It is ready to mount on the table. The last x axis got the flapper wheel run over it. It was nice and shiny for a few moments until I coated it with gloss black paint. Tomorrow hopefully I will finish it and start the y-carriage setup.

Well rails are done except that I need to replace one. Ordered new v groove rail from McMaster Carr. Y axis is in progress. As soon as I get two rectangular tubes cut and welded I am going to move the machine indoors. I do not want to do any of the electrical work outdoors.

Here is a picture of the base. Tomorrow I dragging the Shopsmith out there and cut up all the scrap wood. I know my neighbors will appreciate it.